Illicit Obsessions
by Alexis.Black.Snape
Summary: For Peter Pettigrew, the descent into darkness began in her arms.
_Oh, Merlin… what am I going to do?_

The thought worried his brain. It gnawed ravenously at the frayed edges of his mind until he felt he would unravel. Peter shifted on the worn, hard chair and looked through the open door of his bedroom.

On his bed, Narcissa sighed in her sleep. Her nude body gleamed in the faint moonlight against the faded sheets. The bruises on her face and across her hip had faded away completely. Peter let his eyes travel slowly up the curve of that hip to the firm, pale flesh of her ample breast. He remembered how it felt to cup them, the sensuous weight of them in his hand and how they tasted.

Abruptly his hand clenched into a fist and the ragged nails cut into his palm. He turned away from the vision of the fallen angel that graced his sagging bed - an angel who had seduced him numerous times since the moment she begged for his help.

 _What if James comes by?_

Hunched over the small, scratched table that served its duty as both desk and dining table, Peter replayed in his mind the previous events that had led up to this point.

He had left the restaurant in a fit of depression and walked straight into a downpour. Remus and Sirius had been fighting again: Sirius prodding Remus with pointed questions about his whereabouts during the last few full moon nights and the identity of the werewolf who had turned him; Remus inquiring as to why Sirius felt the need to track his movements. Things had gotten rather heated and had almost come to blows.

It wasn't the first time. A tension had invaded their tight-knit friendship like a relentless poison. Dark times seemed to loom overhead, and the events of the past months sawed at the bonds of their friendship. You-Know-Who had grown in power. Dumbledore had invited the Marauders to join the Order of the Phoenix. Then James and Lily had married and openly defied You-Know-Who. Without James to balance them, to diffuse Sirius' increasing temper, the friendship had become strained.

Peter had departed after Remus stalked out in disgust. Instead of following his once close friend, Peter had taken a side alley that after a few twists emptied out onto Knockturn Alley. The rain accumulated in a long, snaking path up the middle of the passageway. Instead of washing away the filth that accrued along the sides and in the corners, the rain simply thrust it to the center, resulting in a slushy mix. Peter had wrinkled his nose at the rising stench and thought about how it reminded him of the River Thames. As he had approached the final corner, he heard her cry out.

"Lucius! Don't, please!"

There had been the distinct sound of something heavy striking flesh and the splash of a falling body. Peter had froze in his tracks as footsteps stalked away and faded into the distance. The sound of sobbing had drew him forward out of curiosity. Cautiously, Peter had sidled against the wall and leaned around the corner.

Curled on the ground in the middle of the filth-ridden slurry was Narcissa Malfoy. He stumbled forward out of the shadows and stopped. Narcissa had turned blood-shot eyes at him through limp, flaxen hair. She had clutched her right cheek; it was already showing signs of swelling from the blow her husband had dealt her.

"Pettigrew?" she had whispered in a broken voice.

He had wanted to leave right then, but he couldn't. Ever since his first year at Hogwarts, he had nursed a secret affection for Narcissa from afar. Elegant perfection, she was an angel carved from the purest alabaster and just as cold. Always out of reach, Narcissa never once glanced his way. That didn't stop Peter's affection from growing over time and becoming stronger.

The other Marauders doted on Lily with her fierce loyalty, or the other witty and humorous girls in their House. It was Narcissa Black's image that filled Peter's mind, though, when he sought to assuage his burgeoning desire, alone by himself.

At some point, affection had became a consuming desire; desire had swiftly metamorphosed into obsession. Then he had heard she became Narcissa Malfoy, and he was devastated. How could she have given herself to that slime Lucius Malfoy?

"Help me, please, Peter?" Her pleading had woken him from his trance. Narcissa had reached out a hand, seeking help. Lucius had cast her aside, and she had turned to him.

Peter had swiftly taken her out of the alley to the only place he could think of. Once they had arrived at his flat, he had found himself ashamed. His home was messy, small and unworthy of Narcissa's perfection. She had merely thanked him softly for his kindness.

Haltingly, Narcissa had told him of her life as Mrs. Malfoy over a cup of tea. The marriage was a farce. It had been arranged between their families. Narcissa had had no voice in the matter; neither had Lucius. She had learned swiftly just how much Lucius despised being tied to her. Left to his own devices, he had preferred the company of men. Their marriage had been consummated in the quickest, roughest manner possible. She could hardly accuse him of raping his own wife, could she?

To all appearances, they had appeared to be a loving couple. Appearances were deceiving. Lucius had began to beat her when Narcissa failed to immediately fall pregnant with an heir. The incident Peter had overheard was but one in a series of such that had made up her married life.

"He hates me," she had whispered, wrenching the wedding band off her finger and letting it fall to floor. "He says no man could find me desirable."

Peter had disagreed. He had tried to console her, slipping an arm around her shoulder and letting her cry. Peter had hardly moved as he held her close. He had longed to stroke her hair but didn't dare move. It would break the spell, and he hadn't wanted the moment to end. Here was his dream, in his arms.

When her tears finally dried, Narcissa had asked whether Peter found her desirable, and as he looked down at her, their lips met. What followed was inevitable. Peter had showed Narcissa in no uncertain terms how desirable he found her. He had whispered it in her ear as he undid the buttons on her stained clothes and laid bare her body; he had showed it with his intimate caresses; he had whispered it aloud when he found sweet release.

That had been a month ago.

Narcissa had not left Peter's flat in all that time. On numerous occasions, he had indulged in his desires and worshiped her body; never once did she stop him. She had willingly slipped into his arms and offered him pleasure of the sort he had only fantasized. They had done things Peter could hardly believe. He was sure the sounds of their frequent lovemaking would wake the neighbors. When he was sated, Narcissa would confide in him she had never had such a consummate or imaginative lover. With him she had found what had been missing in her life.

During the rare times when Peter left to purchase food and other necessities, he had always returned to find Narcissa waiting and his flat tidied. All had been perfect until the glowing stag had delivered its message. Thankfully, Narcissa had been asleep when it arrived. The message was from James, wondering where Peter had gotten to and why he had missed the last Order meeting. Was anything wrong?

 _As if James would understand,_ Peter thought bitterly. _He hasn't been much of a friend since getting married, has he? Too busy with Lily. A month passes and not one of them has even tried to contact me. And what about the Order? Dumbledore hardly acknowledges my presence. It's always James this, Lily that, and Sirius. Bloody hell, even Remus gets more attention._

Staring blankly at the desk, another thought struck Peter.

 _What if James decides to pay a visit? Or worse, Sirius?_

The thought nibbled at his consciousness, incessantly biting at his mind until sleep became impossible. Without thinking, Peter lifted a hand up and chewed his already ragged nails until he tasted blood.

 _What would I do if anyone came by and found Narcissa in my bed? Would they disown me outright? Why should I even care? It's obvious they don't give two shillings about me._

He argued with himself, mentally bickering back and forth. As much as Peter resented being treated as an unnecessary fifth-wheel, though, he had no other friends. He had no one besides Narcissa.

"Peter?"

He twitched in his seat and jerked around to see Narcissa reclining on the bed. She tossed her long hair over her bare shoulder with languid grace. Then she slid her hand up the flat plane of her stomach to her chest. Peter's eyes tracked the movement and his mouth parted slightly. Desire stirred.

"I'm cold, Peter. Come to bed and warm me."

He pushed himself to his feet, not even hearing the chair fall over backwards. All he could focus on was her breathy voice as he walked back to the bedroom.

"We can do something different this time." She caught her pale lower lip between her teeth briefly. "Something naughty."

While Peter stood next to the bed, Narcissa slowly undid his trousers with long, cool fingers. Then she pulled him down next to her. Before he could protest, she slipped on top and pulled out her wand.

"This is what we'll do," she murmured. She bound his hands to the headboard with magic and slowly began to torture him with first her tongue and then her body.

On the cusp of ecstasy, the door to his flat burst open. Bound to the bed, Peter opened his eyes. The sound of muted clapping announced the arrival of Lucius Malfoy. He surveyed the surroundings with obvious contempt.

Peter squeaked and felt all the desire in his body evaporate. He struggled in vain against his bonds. Narcissa moaned as he bucked beneath her.

"Narcissa," he greeted his wife. "Wife, aren't you finished?"

With a pout on her lips, Narcissa climbed off of Peter and eyed her husband. "Your timing is as vexatious as ever, my love. Could you not have waited a few more minutes?"

She walked naked over to her husband and kissed him. Lucius slid a gloved hand down and splayed it against the small of her back in a possessive manner. Unable to believe what was happening, Peter shook his head in disbelief.

"Get dressed," her husband murmured her, spanking her playfully. "I will finish later what he started." As Peter watched, Narcissa gathered her robes and left the room.

Lucius waved his wand and the chair from the other room moved across the floor. He dusted it off distastefully and seated himself.

"Tell me, Peter Pettigrew," he drawled coldly, "did you enjoy my wife this past month?"

Peter finally found his voice. "Cissy!" he cried out. Then he turned his concentration inward and sought the magic – the sheer will – to transfigure himself into a rat.

Before Peter could invoke the change, Lucius swiftly lifted his wand and hissed, _"Crucio!"_

Unimaginable pain slammed into his body. He thrashed in agony against the sheets where moments before he had writhed in pleasure under Narcissa's ministrations. He couldn't breathe. Blood flooded his mouth from where he bit his tongue.

An eternity later, the pain receded.

"She is my wife. You would do well to remember that and address her as Mrs. Malfoy." Cold rage distorted Lucius' features for a moment. Then the smooth, genial mask slid back into place.

"Now, Pettigrew, answer my question. Did you not enjoy my wife? And do not try to become a rat again, or I will do something far worse." Lucius pointed his wand at Peter's groin.

Naked and trussed up in his own bed, Peter could only whimper. A trickle of blood seeped out of his mouth. He didn't know how to answer. Instead, he curled his legs up protectively.

Narcissa entered the room and stood behind Lucius, one hand placed on his shoulder. Her husband reached up and pulled her hand to his lips, kissing the wedding band that now glinted on her finger. She gazed down on Peter with a look on her face as if there was something particularly unpleasant smelling nearby.

"You might as well tell Lucius what he wants to know, Pettigrew. I've seen him do things that would haunt your nightmares. On the other hand, you can waste time and scream while he teaches you another lesson. No one is going to come and rescue you, either way."

At the mention of a rescue, a flicker of hope flared in Peter's chest. Narcissa threw back her head and laughed. Lucius chuckled, but his eyes were hard as granite.

"Poor, pitiful Pettigrew," Narcissa continued, stepping around her husband to stand directly in front of her illicit lover. "Your neighbors are quite used to the sound of screams and moans coming from your flat. A few more will hardly raise any eyebrows. Of course if your little friends should come sniffing about, well, they would soon learn of the woman who has been keeping you company all this time. You see, I'm afraid while you were out yesterday, I bumped into that gossip-monger of a landlady, Mrs. Eriksson. I do believe she might have recognized me."

Peter trembled. His nose twitched and his fingers clawed the air helplessly.

"I don't think your friends would think very much of you, having an affair with the wife of Lucius Malfoy and spilling their precious secrets."

Peter jerked his arms in vain. "I've never told you anything."

"No," Lucius agreed pleasantly, "but you will, Pettigrew. You will tell our Dark Lord everything you know." He nodded to Narcissa before continuing. "And in exchange, I will allow you to continue keeping Narcissa company. The only conditions are your unquestioning loyalty and the promise that you will no longer pollute her womb."

Dropping to her knees on the thin mattress, Narcissa slithered across the sheets towards Peter. Her tongue snaked out between her lips. Then she ducked her head down, causing Peter sucked in a shuttering breath.

Caught between fear and illicit lust, Peter clung to the thin strands left of his principals for a brief moment before surrendering to his obsession.

 _ **~ Finite ~**_

 _ **Author's Notes**_

This story was written in response to a challenge hosted years ago at MNFF about what made Peter Pettigrew betray his friends.

Story originally submitted at other locations under the penname Snapes_secret and Snape's Talon.


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